<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>

</head>
<body>
<img id="light" src="../img/off.gif" onclick="fun();">
<img id="light2" src="../img/off.gif">

<script>
    function fun(){
            alert('我被点了');
            alert('我又被点了');
        }

    function fun2(){
        alert('咋老点我？');
    }

    //1.获取light2对象
    var light2 = document.getElementById("light2");
    //2.绑定事件
    light2.onclick = fun2;
</script>
</body>
</html>